To carry out an international and domestic animal surveillance program focused on virologic, epidemiologic, and disease surveillance with emphasis on the rapid characterization of influenza viruses with pandemic potential. This includes the development and/or maintenance of a network capable of rapid biological, molecular and serological characterization of influenza viruses identified in animals, including but not limited to aquatic and land-based birds, wild birds, live animal markets, and other settings that provide enhanced opportunities for the reassortment of influenza A virus subtypes and close contact with humans. Additional areas of interest include, but are not limited to, serosurveillance studies of humans in close contact with animals, pathogenicity studies in animals, the role of migratory birds in the spread of influenza viruses, and the effectiveness of animal control measures. To determine the molecular, ecologic and/or environmental factors that influence the evolution, emergence, transmission and pathogenicity of influenza viruses, including studies on animal influenza viruses with pandemic potential and to characterize the immune response to influenza infection and/or vaccination to improve understanding of the immune correlates of protection and cross-protection.